1. Technical Field
This invention is in the field of package ties in the form of plastic bands. U.S. patent main class 24, subclass 16PB contains a large number of these.
2. Background
An example of an early patent in subclass 16PB is U.S. Pat. No. 3,965,538 for an Integral Cable Tie, issued Jun. 29, 1976 to Cavenay et al. and assigned to Panduit Corp., incorporated herein by reference. This is for a cable tie that is by now well known in design. It is a one piece flat plastic strap having a rectangular enclosure (“frame” in the patent) at one end with a tapered tip at the other. The body of the strap between the enclosure and tip has a plurality of equally spaced ridges or teeth on one side. The enclosure has an entrance (throat) for the tip on the same side of the strap as the teeth and an exit on the opposite side. Within the enclosure is a hinged pawl, also having several teeth, that engages the strap teeth after insertion of the strap. The strap teeth and pawl are designed to make insertion of the strap through the enclosure easy and pulling the strap out in reverse difficult. Thus, when wrapped around a bundle of electrical cables, they may be secured together or to, e.g., a bulkhead in an aircraft, etc. Normally, the tie is undisturbed for the life of the equipment. If it has to be removed, it is cut with pliers. Because the strap, enclosure, and internally hinged pawl are all designed as a single piece of injection molded plastic and installation is generally fast, the cost for each tie is small compared to other solutions such as lacing cords. As cable ties go, this design produced an apparently very superior product. The one possible drawback is that it is a bit complex and requires care in mold making and injection molding the parts.
It may be of interest that this patent was initially invalidated by a U.S. district court as being obvious in view of the prior art in cable ties. This decision was appealed up to the U.S. Supreme Court which sent it back to the Court of Appeals for the Federal Circuit for reconsideration. The Court of Appeals followed the law as indicated by the Supreme Court, but still decided that the invention in this patent (and two others) was not obvious and therefore the patent was valid. The court seemed to be impressed by the low ratio of insertion to removal force and the outstanding commercial success. (The decision is published at 810 F.2d 1561 or 1 USPQ2d 1594.)
As of this writing, main patent class 24, subclass 16PB contains almost 670 patents, including cross references, going back to U.S. Pat. No. 3,930,287 issued on Jan. 1, 1976. A fair number are titled “Cable Tie” or similar. There are a lesser number titled “Security Seal” or similar. An example of a security seal is U.S. Pat. No. 4,501,049 for a Disposable One-Piece Security Sealing Device, issued Feb. 26, 1985 to Adamson and assigned to Envopak Limited (Kent, England). It is “primarily intended to surround the neck of bag [a mail sack appears to be illustrated] or like package.” This is like the patent described above, but has an extension of the main strap that goes around the pawl enclosure and spreads out into a flat extension about twice the width of the strap. Additionally, a “line of weakness” separates the extension and the enclosure and extends around the enclosure and makes its way along a serpentine path to the other side of the strap. Pulling the extension causes the strap to separate and release from the bag. Additional features include molded-in spikes to hold the strap against a cloth, a molded wire loop for affixing a label, and an anti-tampering design for the teeth, enclosure and pawl.
While the above referenced patents disclose designs that are suitable for their primarily intended purpose, there is another use for plastic bands. This is in that part of the distribution and supply industry that uses tote boxes. These are used in distribution networks that supply retail outlets with dry goods that are diverse as to shape and quantity. For example, restocking a drug store requires a mixture of products, most of which are in an assortment of small packages. There are a number of different designs for tote boxes that generally include a rectangular box about two cubic feet in size with a lid or cover. Typically, there are grooves that keep the lid oriented and may have retaining functions. Quite often there are matching holes in the lid and boxes arranged near an edge and lip, respectively, so that cable ties can pass through the holes and retain the lid to the box. An early example is U.S. Pat. No. 3,360,162 for a Tote Box, issued Dec. 26, 1967 to Miles, wherein it is claimed that, to discourage pilferage, a sealing element may be passed through aligned slots in the lid and a flange extending from the top of the box.
The sealing elements in this patent have a dual purpose of providing a modicum of security but, primarily, keeping the lid on the box from warehouse to retail outlet. There are some security seals for tote boxes that do provide security, but do not act to hold the lid tightly to the box. Currently, the industry standard is to use the same ties that are used for bundling electrical cables. On arrival at the retail outlet, single sided knives, wire cutters, or hefty scissors are used to cut the cable tie to open the lid. Use of a sharp tool produces a safety issue, can damage the tote box, and keeping track of it slows down the operation. An improved retaining means is required that could be manually separated without tools, yet strong enough to retain the lid to the box during transit. Currently, the industry prefers to use a cable tie once rather than return retainers back with the tote boxes. (Because many cables ties are all plastic, they can be recycled.) The one-time use and large volume require that any improved tote box retainer cost no more than currently available cable ties.
This tote box application differs from sealing the neck of a bag or sack. Usually, if a security seal is pulled tightly around the neck of a full sack, it will be well fixed with respect to the sack. Thus, the need in Adamson's design to pull an extension at right angles to the strap, then switch direction and follow a serpentine path would be feasible. Tote box retaining holes, however, are usually larger than the straps of the ties used. Even when a retaining strap is tight enough so that the lid cannot come off, which is generally all that is demanded, the strap may rotate around itself and rock back and forth. This makes a tear-off extension that needs pulling in multiple directions undesirable. Some tote boxes are designed so that any straps remain inside the outer box dimension to prevent damage to the retainer or personnel. This can put the retainer in a confined space so that it is awkward to remove.
Even though tote boxes and cable ties are at least about 30 years old, there is still an unfulfilled need in the market, for a tote box retainer strap that is simple and inexpensive to make, yet easy to remove without tools while strong enough to retain the lid on the box.